Photographic apparatus for use in daylight and artificial light

ABSTRACT

A camera wherein one or more corrective filters are moved into or from the path of incoming scene light when the spectral composition of such light matches or does not match the spectral sensitivity of film which is used in the camera. The filter or filters can be displaced by an electric circuit having one or more photosensitive resistors which can change the condition of a relay, electromagnet or transistor whereby the latter energizes one or more electromagnets which are directly or indirectly connected with the filter or filters.

United States Patent Scheibel et al.

[4 1 June 27, 1972 PHOTOGRAPHIC APPARATUS FOR USE IN DAYLIGHT ANDARTIFICIAL LIGHT [72] Inventors: Josef Schelbel, Over-Morlen; Karl-HeinzSchadt, Schwalbach, both of Germany [73] Assignee: Niezoldi & KramerGmbH, I M unich Germany [22] Filed: May 15, 1969 [21 Appl. No.: 824,880

[30] Foreign Application Priority Data May 16, 1968 Germany ..P 17 72445.7

[52] US. Cl. ..'...95/10 CE, 95/11 R, 352/78 C [51] Int. Cl. ..G0lj 1/22[58] Field otSearch ..95/1OC, ll;352/72, 141,78

[56] References Cited UNITED STATES PATENTS 3,472,137 10/1969 Galbraith..95/1 0 C 3,176,599 4/1965 Anwyl ..95/l0 3,314,344 4/1967 Anwyl et a]..95/1O 3,452,658 7/1969 Krull et al ..95/ll 3,500,730 3/1970 Matsubaraet a1. ..95/l0 Primary Examiner-Samuel S. Matthews AssistantExaminer-Fred L. Braun Attorney-Michael S. Striker [57] ABSTRACT 4Claims, 8 Drawing Figures PATENTmJum m2 3.672.268

sum 1 or a iq/m1. fA-l,..

ATTORNEY CROSS-REFERENCE TO RELATED APPLICATION This application relatesto improvements in photographic apparatus disclosed in the copendingapplication Ser. No. 568,653 of Krull et al., now US. Pat. No.3,452,658, which is assigned to the same assignee and to which referencemay be had if necessary.

I BACKGROUND OF THE INVENTION The present invention relates tophotographic apparatus in general, and more particularly to improvementsin cameras which employ corrective filters. Such filters enable a camerato make satisfactory exposures with daylight film in artificial light ordaylight and/or to make satisfactory exposures with artificial lightfilm in daylight or artificial light.

The US. Pat. No. 3,452,658 discloses a camera wherein the means formoving filters to and from registry with the optical axis comprises alight meter which is in circuit with two photosensitive resistors one ofwhich reacts to daylight and the otherto which reacts to artificiallight. The output member of the meter assumes a position which is afunction of the resistance of photosensitive elements and is further afunction of spectral sensitivity of inserted film. Such position of theoutput member is detected by a scanning device which serves as a meansfor affecting movement of an appropriate corrective filter into or awayfrom registry with the objective lens. The mechanism which couples thefilters with the output member of the light meter is rather complicatedand bulky.

' SUMMARY OF THE INVENTION An object of my invention is to provide anovel and improved camera whereinone or more built-in corrective filterscan be moved into and away from the path of incoming scene light in anovel and improved way;

Another object of the invention is to provide the camera with novelfilter displacing means.

A further object of the invention is to provide a camera which canemploy films of different spectral sensitivity and wherein such filmscan be employed in daylight or artificial light.

An additional object of the invention is to provide a camera wherein themeans which displaces one or more filters can be automatically adjustedas a function of spectral sensitivity of inserted film.

A further object of the invention is to provide a camera wherein themeans for displacing one or more filters need not include a moving-coilmeasuringinstrument.

The invention is embodied in a photographic apparatus, for example, in amotion picture camera, which comprises objective means positioned toadmit scene lightto photographic film, filter means movable between aplurality of positions to thereby influence the characteristics of scenelight which is admitted by the objective means, and displacing means formoving the filter means between its positions in dependency on spectralcomposition of scene light. The displacing means v comprises switchingmeans (e.g., a relay or one or more transistors) having a plurality ofconditions, photosensitive receiver means (preferably including twophotosensitive resistors one of which reacts to daylight and the otherof which reacts to artificial light) in circuit with the switching meansand exposed or exposable to scene light to thereby change the conditionof the switching means as a-function of changes in spectral compositionof scene light, and adjusting means (preferably including one or moreelectromagnets) for effecting movements of filter means in response tochanges in condition of the switching means. The filter means mayinclude one or more discrete filters movable into and from the path of.

claims. The improved photographic apparatus itself, however,

both as to its construction and its mode of operation, together withadditional features and advantages thereof, will be best understood uponperusal of the following detailed description of certain specificembodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagram of an electricfilter displacing circuit which embodies one form of our invention;

FIG. 2a, illustrates a portion of a photographic apparatus whichembodies the displacing circuit of FIG. 1, the filters being shown inpositions they assume when the apparatus is loaded with artificial lightfilm and is to be used in daylight;

FIG. 2b shows some of the structure of FIG. 2a but with the filters inpositions they assume when the apparatus is loaded with daylight filmand is to be used in daylight;

FIG. 20 shows the structure of FIG. 2b but with the filtersin positionsthey assume when the apparatus is loaded with daylight film and is to beused in artificial light;

FIG. 2d shows the structure of FIG. 2b or 20 but with the filters inpositions they assume when the apparatus is loaded DESCRIPTION OF THEPREFERRED EMBODIMENTS FIG. 1 shows an electric displacing circuit whichis a bridge circuit and comprises two series-connected photosensitiveresistors l, 2 and two series-connected fixed resistors 3, 4. Theresistors l, 2 and 3, 4 are respectively in series with an energy source5, e.g., a battery. When the resistors l, 2 are completely shielded fromlight, their resistance respectively equals the resistance of fixedresistors 3, 4. The switching means of the circuit comprises a polarizedrelay 6. The positioning of the photosensitive resistors I, 2 behind twocorrective filters F and 1- is such that the resistor 1 reacts to (i.e.,its resistance decreases in) daylight and that the resistance of theresistor 2 decreases in artificial light. The bridge circuit is balancedwhen the resistors I, 2 are fully shielded from light and the switchingrelay 6 is deenergized so that its switch member 6b assumes the neutralposition shown in FIG. I. If the camera which embodies the circuit ofFIG. 1 is used in artificial light which impinges on the photosensitiveresistor 2,-the potential of a tap 7 increases with reference to the tap8, Le, a current flows from the tap 7 toward the tap 8 and the switchmember 61: of the thus energized switching relay 6 moves into engagementwith a fixed contact 6a. When the photosensitive resistor l is exposedto a daylight, the potential of the tap 7 decreases with reference tothe tap 8 whereby a current fiows through the diagonal branch of thedisplacing circuit in a direction from the tap 8 toward the tap 7 sothat the energized switching relay 6 moves its switch member 6b intoengagement with a second fixed contact 60. The contacts 6a, 6crespectively connect adjusting electromagnets l0, 9 in parallel with theenergy source 5 when such contacts are engaged by the movable switchmember 6b.

FIG. 2 shows a diskor cup-shaped holder 11 which is turnable by amotion-transmitting device 32 between two'end positions in response toinsertion of film into the chamber 34 of the camera body or housing 33.When the chamber 34 receives a magazine or cartridge 35 containingdaylight film, the device 32 automatically moves the holder 11 to. theposition 12; this holder is caused by device 32 to assume the position13 in response to insertion of a cartridge containing artificial-lightfilm. A filter means including a filter-carrying sector-- shaped support14 is mounted for angular movement about the axis of the holder 11 andis provided with three discrete corrective filters each of which can bemoved into registry with the optical axis of the camera, i.e., in frontof the film window or gate and behind an objective lens 30. The upperfilter 15 is a red filter, the lower filter 16 is a blue filter, and thecentral filter 17 is simply an opening which is free to admit all of thescene light. The support 14 further comprises a radially extending armor armature 18 which is located between the adjusting electromagnets 9and 10. These electromagnets are mounted on the holder 1 l in such a waythat each thereof can attract the arm 18 in response to engagement ofthe switch member 6b with the corresponding fixed contact 6c or 6a ofthe switching relay 6. Ifthe photosensitive resistor 1 is exposed todaylight and the camera contains artificial-light film, the relay 6moves theswitch member 6b into engagement with the contact 60 andthereby connects the adjusting electromagnet 9 with the energy source 5.The electromagnet 9 is energized and attracts the arm 18. This is shownin FIG. 2a which illustrates the holder 11 in the position 13 (thecamera is loaded with artificial-light film). The red filter 15 is thenlocated in registry with the optical axis of the objective lens 30. Ifthe camera contains daylight film so that the holder 11 assumes theposition 12 (FIG. 2b), the energized adjusting electromagnet 9 causesthe support 14 to assume a position in which the filter l7 registerswith the optical axis of the lens 30.

When the camera is used in artificial light, the resistance of thephotosensitive resistor 2 decreases so that the switch member 6b of theswitching relay 6 engages the contact 6a to connect the adjustingelectromagnet 10 with the energy source 5. The thus energizedelectromagnet l attracts the arm 18 in a manner as shown in FIG. 2c or2d. If the camera contains daylight film (FIG. 2c), the holder 1 l andthe support 14 assume such positions that the blue filter 16 moves intoregistry with the optical axis of the objective lens 30. The window l7registers with the optical axis (FIG. 2d) if the camera containsartificial light film while the exposure is being made in artificiallight.

FIG. 2a shows schematically the motion transmitting device 32 which isarticulately connected to the holder 11 to move the latter from theposition 12 to the position 13, or vice versa, depending upon whetherthe chamber 34 of the camera housing 33 accommodates a cartridge 35which contains a first type of film or a different second type of film(e.g., daylight film or artificial light film). The cartridge 35 isprovided with suitable coding means which is indicative of thesensitivity of film and can engage the device 32. I

If desired, the holder 11 can be adjusted by hand to thereby select theinitial position of the support 14 independently of the condition of therelay 6, i.e., to account for the type of film which is used in thecamera.

If the camera is designed to receive only one type of film i.e., film ofa given spectral sensitivity), the displacing circuit of FIG. 1 isreplaced with the bridge circuit of FIG. 3 which employs a non-polarizedrelay 19 serving as a switching means. The switch member 19b of therelay 19 is movable into or away from engagement with a contact 19awhich can connect the energy source in circuit with an adjustingelectromagnet 20. The diagonal branch of the circuit further comprises arectifier, here shown as a diode 21, whose anode is connected to the tap7 and whose cathode is connected with the winding of the switching relay19. It is assumed that the chamber in the housing of the camera whichembodies the displacing circuit of FIG. 3 is designed to acceptcartridges containing artificial light film.

When the photosensitive resistor 2 is exposed to artificial light, itsresistance decreases so that the potential at the tap 7 rises. A currentflows from the tap 7 toward the tap 8 to energize the switching relay 19so that the switch member 19b engages the contact 19a and energizes theadjusting electromagnet 20which moves a red filter (not shown) away fromregistry with the optical axis of the camera objective. If the resistorl is exposed to daylight, the potential of the tap 7 becomes negativerelative to the tap 8 so that a current tends to flow from the tap 8toward the tap 7; however, the flow is prevented by the rectifier 21 sothat the switching relay 19 remains deenergized and preventsenergization of the adjusting electromagnet 20. The red filter thenremains in registry with the optical axis.

Referring to FIG. 4, there is shown a third displacing circuit whichcomprises a switching means in the form of a transistor 22. The voltagedivider for the base potential of the transistor 22 comprises twophotosensitive resistors 23 and 24. The collectorv of the transistor 22is connected with an adjusting electromagnet 25. The photosensitiveresistors 23, 24 are mounted behind corrective filters F, and F, whichinsure that the resistance of the resistor 23 decreases in daylight andthat the resistance of the resistor 24 decreases on exposure toartificial light. The circuit further comprises an energy source 26. Itis assumed that the camera is designed for use with artificial lightfilm. The resistances of the photosensitive resistors 23, 24 areselected in such a way that the switching transistor 22 blocks the flowof current when the resistors 23, 24 are shielded from light, i.e., thatno current flows through the winding of the adjusting electromagnet 25.This electromagnet displaces a filter to move it to a position in whichthe filter extends across the path of light admitted by the objectivewhenthe camera is used in daylight, i.e., when the spectral compositionof scene light does not match the spectral sensitivity of (artificiallight) film. If the camera is designed for use with daylight film, theelectromagnet 25 moves the filter to operative position when the camerais used in artificial light.

When the resistor 24 is exposed to artificial light, the base potentialof the transistor 22 (which can be pnp transistor) becomes positive andthe transistor continues to block the flow of current. If the resistor23 is exposed to daylight, the base potential becomes negative, i.e.,the signal voltage increases so that the transistor conducts current andthe collector current effects energization of the electromagnet 25. Theelectromagnet 25 then causes the filter to move to a position in whichthe filter is in registry with the optical axis. The operation of thecircuit shown in FIG. 4 is substantially the same if the photosensitiveresistor 24 is replaced with a fixed resistor.

It is further clear that the camera which embodies the displacingcircuit of FIG. 4 can include two built-in filters one of which is heldin operative position when the spectral composition of scene lightmatches the spectral sensitivity of film and the other of which is movedto operative position by electromagnet 25 when the camera containsdaylight film and is used in artificial light or vice versa. Stillfurther, the camera which embodies the displacing circuit of FIG. 4 canutilize a single filter which is held in operative position when thespec tral composition of scene light matches the spectral sensitivity offilm but is moved away from the path of scene light admitted by theobjective lens when the camera contains daylight film and is used inartificial light, or vice versa.

It is also within the purview of our invention to employ as theswitching means of the displacing circuit a relay or an electromagnetwith a switching member having two switching positions without automaticreturn movement to a given position, and a dividing system for eachdirection of action. Such dividing circuit consumes very littleelectrical energy because it reacts to short signals and thereupon fixesthe switching member in its momentary position during the intervalbetween two successive changes in spectral composition of scene light.

The just described modification is shown in FIG. 5 wherein theelectromagnets 9, l0 constitute the switching means of the bridgecircuit. Thus, the relay 6 of FIG. 1 can be dispensed with. When thephotosensitive resistor 2 is exposed to artificial light, a currentflows from the tap 7 between the photosensitive resistors l, 2, througha diode 36, the electromagnet 10 and to the tap 8 between the fixedresistors 3, 4. A second diode 37 prevents the current from flowingthrough the electromagnet 9 in a direction from the tap 7 toward the tap8. The electromagnet 10 is energized and attracts the armature 18 tothereby move the support 14 to a position in which the filter 16registers with the objective lens 30 if the camera contains daylightfilm. A detent spring 38 which is secured to the holder 11 by means of asuitable fastener 39 automatically retains the armature 18 in theillustrated position when the electromagnet is deenergized.

If the photosensitive resistor 1 is exposed to daylight, a current flowsfrom the tap 8, through the electromagnet 9 and diode 37, and to the tap7. The diode 36 prevents the flow of such current through theelectromagnet 10. The energized electromagnet 9 attracts the armature 18and moves the window 17 into registry with the objective lens 30 (itbeing as sumed that the camera contains daylight film). The detentspring 38 thereupon maintains the armature in its right-hand endposition even if the electromagnet 9 is deenergized. The electromagnets9, 10 are strong enough to effect deformation of the detent spring 38when one thereof is energized in response to exposure of resistor l todaylight or resistor 2 to artificial light;

As stated above, an advantage of the structure shown in FIG. 5 is that ashort-lasting current impulse sufiices to effect appropriate adjustmentof the support 14. This is due to the provision of the detent spring 38which automatically retains the armature 18 in position until theelectromagnet 9 or 10 is energized again. The resulting savings inelectrical energy are particularly important if the energy source 5 is abattery or a cell.

If desired, the filter or filters can be reciprocated to and fromoperative positions, preferably at right angles to the optical axis.

An important advantage of a camera which embodies the filter displacingmeans of our invention is that such displacing means occupies littleroom and that it can immediately react to replacement of film having afirst spectral sensitivity with a film of a second spectral sensitivityor vice versa, as well as that it can immediately react to a change inspectral composition of scene light to move one or more correctivefilters into or away from the path of scene light which is admitted bythe objective lens. In this way, the spectral composition of light whichis permitted to reach the film always matches the spectral sensitivityof film which is being used for a particular exposure or for aparticular series of exposures.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featureswhich fairly constitute essential characteristics of the generic andspecific aspects of our contribution to the art.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.

We claim:

1. In a photographic apparatus, a combination comprising objective meanspositioned to admit scene light to photographic film; filter meansmovable between plural positions to thereby influence thecharacteristics of scene light which is admitted by said objectivemeans; displacing means for moving said filter means between saidpositions in dependency on spectral composition of scene light, saiddisplacing means comprising electric switching means having a pluralityof conditions, photosensitive receiver means in circuit with saidswitching means, said receiver means being exposed to scene light andbeing operative to change the condition of said switching means as afunction of changes in spectral composition of scene light, saidphotosensitive receiver means including a first photosensitive resistorwhich reacts to daylight and a second photosensitive resistor whichreacts to artificial light, said switching means comprising a firstelectromagnet energizable in response to exposure of said first resistorto daylight and a second electromagnet energizable in response toexposure of said second resistor to artificial light, and adjustingmeans for effecting movements of said filter means in response tochanges in the condition of said switching means, said adjusting meansincluding armature means which is movable to first and second positionson energization of said first and second electromagnets, respectively;and detent means for yieldably holding said armature means in eitherposition.

2. In a photographic apparatus, a combination comprising a housing;color filter means movable in said housing between plural positions tothereby influence the characteristics of incoming scene light, saidfilter means including a daylight filter and an artificial light filter;displacing means for moving said filter means between said positions independency on the spectral composition of scene light, said displacingmeans comprising electric switching means having a plurality ofconditions, photosensitive receiver means connected in circuit with saidswitching means, exposed to scene light and operative to change thecondition of said switching means as a function of changes in spectralcomposition of scene light, said photosensitive receiver meanscomprising a pair of series-connected photosensitive resistors one ofwhich reacts to daylight and the other of which reacts to artificiallight, first and second fixed resistors connected in parallel with saidphotosensitive resistors and each having a resistance equaling theresistance of a different one of said photosensitive resistors when therespective photosensitive resistor is shielded from light, and adjustingmeans for effecting movements of said filter means in response tochanges in the condition of said switching means, said adjusting meanscomprising first and second electromagnet means respectively energizableon exposure of said first and second photosensitive elements to daylightand artificial light, respectively; and holder means supporting saidfilter means and said electromagnets and movable between two positionsto thereby select the initial position of said filter means independency on the type of film which is used in the apparatus, theinitial position of said filter means in one position of said holdermeans being appropriate when the apparatus contains daylight film andthe initial position of said filter means in the other position of saidholder means being appropriate when the apparatus contains artificiallight film.

3. A combination as defined in claim 2, further comprising means formoving said holder means between said positions thereof.

4. A combination as defined in claim 3, wherein said means for movingsaid holder means is actuatable in response to insertion offilm-containing cartridges into said housing.

1. In a photographic apparatus, a combination comprising objective meanspositioned to admit scene light to photographic film; filter meansmovable between plural positions to thereby influence thecharacteristics of scene light which is admitted by said objectivemeans; displacing means for moving said filter means between saidpositions in dependency on spectral composition of scene light, saiddisplacing means comprising electric switching means having a pluralityof conditions, photosensitive receiver means in circuit with saidswitching means, said receiver means being exposed to scene light andbeing operative to change the condition of said switching means as afunction of changes in spectral composition of scene light, saidphotosensitive receiver means including a first photosensitive resistorwhich reacts to daylight and a second photosensitive resistor whichreacts to artificial light, said switching means comprising a firstelectromagnet energizable in response to exposure of said first resistorto daylight and a second electromagnet energizable in response toexposure of said second resistor to artificial light, and adjustingmeans for effecting movements of said filter means in response tochanges in the condition of said switching means, said adjusting meansincluding armature means which is movable to first and second positionson energization of said first and second electromagnets, respectively;and detent means for yieldably holding said armature means in eitherposition.
 2. In a photographic apparatus, a combination comprising ahousing; color filter means movable in said housing between pluralpositions to thereby influence the characteristics of incoming scenelight, said filter means including a daylight filter and an artificiallight filter; displacing means for moving said filter means between saidpositions in dependency on the spectral composition of scene light, saiddisplacing means comprising electric switching means having a pluralityof conditions, photosensitive receiver means connected in circuit withsaid switching means, exposed to scene light and operative to change thecondition of said switching means as a function of changes in spectralcomposition of scene light, said photosensitive receiver meanscomprising a pair of series-connected photosensitive resistors one ofwhich reacts to daylight and the other of which reacts to artificiallight, first and second fixed resistors connected in parallel with saidphotosensitive resistors and each having a resistance equaling theresistance of a different one of said photosensitive resistors when therespective photosensitive resistor is shielded from light, and adjustingmeans for effecting movements of said filter means in response tochanges in the condition of said switching means, said adjusting meanscomprising first and second electromagnet means respectively energizableon exposure of said first and second photosensitive elements to daylightand artificial light, respectively; and holder means supporting saidfilter means and said electromagnets and movable between two positionsto thereby select the initial position of said filter means independency on the type of film which is used in the apparatus, theinitial position of said filter means in one position of said holdermeans being appropriate when the apparatus contains daylight film andthe initial position of said filter means in the other position of saidholder means being appropriate when the apparatus contains artificiallight film.
 3. A combination as defined in claim 2, further comprisingmeans for moving said holder means between said positions thereof.
 4. Acombination as defined in claim 3, wherein said means for moving saidholder means is actuatable in response to insertion of film-containingcartridges into said housing.